Related Experiment Videos
Clinical and physiological significance of abnormally prolonged central motor conduction time in HAM/TSP
H Shimizu1, Y Shiga, K Fujihara
1Department of Neurology, Tohoku University School of Medicine, Seiryomachi 1-1, Aoba-ku, Sendai 980-8574, Japan.
Insights
Central motor conduction time (CMCT) is prolonged in HTLV-I associated myelopathy/tropical spastic paraparesis (HAM/TSP), reflecting lesion extent. Prolonged CMCT sensitively indicates disease progression and neurological changes in HAM/TSP patients.
Area of Science:
- Neuroscience
- Clinical Neurology
- Medical Research
Background:
- Human T-lymphotropic virus type I (HTLV-I) infection can lead to HTLV-I associated myelopathy/tropical spastic paraparesis (HAM/TSP).
- Understanding the neurophysiological underpinnings of HAM/TSP is crucial for diagnosis and management.
Purpose of the Study:
- To investigate neurophysiological alterations in patients with HAM/TSP.
- To correlate electrophysiological findings with clinical severity in HAM/TSP.
Main Methods:
- Measured central motor conduction time (CMCT), central sensory conduction time (CSCT), and F wave parameters.
- Compared measurements between HAM/TSP patients and healthy controls.
- Analyzed correlations between electrophysiological data and clinical severity.
Main Results:
- Significantly prolonged CMCT in both upper and lower limbs of HAM/TSP patients.
- Prolonged lower limb CSCT in HAM/TSP patients; upper limb CSCT showed no significant difference.
- CMCT and CSCT were significantly correlated; upper limb CMCT correlated with clinical severity.
- F wave parameters were generally normal, but amplitude ratios tended to be higher in HAM/TSP.
Conclusions:
- Prolongation of CMCT is a sensitive indicator of lesion extension in HAM/TSP.
- Findings suggest disinhibition of anterior horn cells contributes to HAM/TSP pathophysiology.
- Electrophysiological measures like CMCT can reflect disease progression in HAM/TSP.
Abstract:
We measured the central motor conduction time (CMCT), central sensory conduction time (CSCT), F wave and mean F wave/M wave amplitude ratio in patients with HTLV-I associated myelopathy/tropical spastic paraparesis (HAM/TSP) and controls. CMCTs in upper (U) and lower (L) limbs were significantly prolonged in HAM/TSP. L-CSCT was significantly prolonged in HAM/TSP, but U-CSCT in HAM/TSP and controls were not significantly different. CMCT and CSCT were significantly correlated in HAM/TSP. U-CMCT, but not L-CMCT, correlated with the clinical severity of HAM/TSP. Although F wave conduction velocity and its occurrence were normal in HAM/TSP, U- and L-mean F wave/M wave amplitude ratio tended to be higher in HAM/TSP, and the L-mean F wave/M wave amplitude ratio was significantly correlated with the L- and thoracic CMCT. These findings demonstrate that the prolongation of CMCT sensitively reflects the extension of the lesions and the disinhibition to the anterior horn cells in HAM/TSP.